Blake, 57, suffers from retinitis pigmentosa, a hereditary disease that disables the rods and
cones, the photoreceptor cells in the eyes that enable us to see in dim and bright light.

There are about 100,000 people in the United States affected by the disease.

Although the diseased cells don't react to light anymore, the neurons beneath them can pass
electronic signals to the optic nerve and finally the brain.

With help, people like Blake can obtain some rudimentary vision.

Late one night last year, Blake's daughter led her outside her home in Huntington, Calif.,
during a full moon.

"I could actually look up and scan the sky and see a flash and point to the moon," Blake said.
"I haven't seen the moon in quite a few years."

In her right eye is an electronic implant built on science developed at six Department of Energy
national laboratories, three universities and a company called Second Sight Medical Products.

Blake is one of 17 patients worldwide who received a second-generation implant called the Argus
II Retinal Prosthesis System.

The implant, inspired by the cochlear implant, which uses electronic stimulation to help the
deaf hear, was the brainchild of Dr. Mark Humayun, now a professor of ophthalmology, biomedical
engineering and cell and neural biology at the University of Southern California.

He started his work more than two decades ago.

"We didn't have proof until 1992, when we had our first patient in the operating room," Humayun
said.

The patient, who had been blind for 50 years, saw spots of light when a temporary implant sent
electric pulses into his retina.

In 2002, Humayun implanted the first permanent device, which had 16 electrodes to stimulate
sight.

The implant was tested on six patients, said Second Sight spokesman Brian Mech.

With training to interpret what the flashes of light mean, some patients could read 1-foot-tall
letters on a wall, navigate an unfamiliar room and recognize objects in a place-setting on a
table.

Patients using the Argus II system can identify a cup, knife and plate faster; 63 percent can
reliably find a door 20 feet away; and 40 percent can follow a line on the floor for 20 feet, Mech
said.

The Argus II system has 60 electrodes, which provide more detail, and works like this: A tiny
video camera mounted in a pair of glasses takes pictures of what's in front of a patient and
transmits each image to a processor worn on the hip.

The processor turns the image into a pattern of electronic impulses that are sent to an antenna
on the side of the glasses. The impulses are directed to a receiver implanted on the side of the
eye. The receiver relays these impulses to the electrodes in the retina.

The impulses travel along the retinal neurons through the optic nerve and to the brain. The
patient sees flashes of light, which the brain uses to make the equivalent of low-resolution
images.

The National Eye Institute has provided nearly $25 million in grants. The Department of Energy
says it spent about $15 million on Argus II and expects to spend $55 million on the Argus III.

Normally, light triggers chemical reactions in rods and cones, which stimulate nerve cells, or
ganglia, and enable us to see, said Elias Greenbaum, corporate fellow and leader of Oak Ridge
National Laboratory's Molecular Bioscience & Biotechnology Research Group.

Greenbaum, whose lab is operated by Columbus-based Battelle, has worked with Humayun for more
than a decade.

"The visual system is much more complex than capturing light," he said.

"The neural cells capture an image that is processed and synthesized, massaged and assembled so
the brain can decode and give an image. The blind have lost the first step."

Instead of re-creating the chemical reaction, "Electrodes are a somewhat crude way of
stimulating the neurons," Greenbaum said. "There's no doubt we can restore a very crude type of
vision."

Blake, a mother of three and a part-time receptionist, underwent the implant surgery in June
2007.

The implant is actually a tiny band placed around the eye. The receiver sits on the side toward
the temple. Humayun cut a small slit in the eye wall and tacked the electrode array to the
retina.

She can follow the sidewalk next to a grass strip and discern a white crosswalk line on dark
pavement as well as the dark edge of a picture frame on the wall.

"One of the big things that's helpful is I can sort my laundry, light and dark clothes, on a
white carpet," Blake said. "If there's no flash, it's light. If there's a flash, it's dark."

She returns to USC every week to retest and fine-tune the system.

"There's definitely been change from the beginning to now," Blake said. "A year ago, I couldn't
sort laundry.

"I can now pick up movement. I can tell which direction a car is going."

Humayun said a large part of the brain is dedicated to vision. When a person loses vision, he
said, there is some evidence that that part of the brain begins helping out with other tasks.

"But it also has an incredible ability to focus on visual input again, if you provide it," he
said.

While trials continue, the partners are building the next model.

Satinderpall Pannu, leader of the Advanced Materials and Technologies Process Group at Lawrence
Livermore National Laboratory in California, is making smaller and more sensitive electrodes.
Battelle helps operate that lab as well.

The electrodes are essentially pixels, Pannu said, and the idea is that the more that there are
in the eye, the clearer the picture.

"That's why we drive to get more pixels," he said. "The Argus III will have more than 200. The
ultimate goal, the fourth, would have more than 1,000 so that patients can recognize faces and read
text of a fairly reasonable size."

But Greenbaum cautioned that researchers aren't sure that the retina will be able to
differentiate among the signals as the electrodes are moved closer together.

"It's as if you have 10 people standing in front of you, and one asks a question," he said. "You
can see who was asking.

"But if you have 100 or 1,000 people in front of you, it's not so easy to resolve."

Tim Schoen, director of preclinical assessment at the Foundation Fighting Blindness, called
electronic implants and therapies using stem cells to try to regenerate rods and cones the two most
promising efforts to restore sight.

However, both face challenges.

Stem cells would have to grow into the highly complex rods and cones and also make the synaptic
connections with the variety of ganglia in the retina, he said.

"The prostheses are stimulating ganglion cells on the order of 10 microns in diameter, but the
electrodes are about 150 microns in diameter. That's like an elephant typing on a typewriter."

Smaller electrodes that don't bleed over should improve vision, he said.

The researchers are striving for implants that would work in the estimated 30 million people
worldwide who have lost their central vision to macular degeneration.

"They are legally blind, but they have their peripheral vision -- they can see the chair and
table," Humayun said. "They need a high-resolution system."

Blake is optimistic about her future as well as the device's.

"My children don't have retinitis pigmentosa, but my grandchildren could," she said. "I want to
get as much research done as I can, for them."